The goal of the proposed project is to understand the relationship between social stress and progression of immunodeficiency disease, and the effects that personality factors may have on this relationship. In humans, AIDS is typically accompanied by socially-induced stresses arising from of sources (e.g. stigma, bereavement). Since early in the AIDS epidemic, the experience of, and ability to cope with such stressors have been proposed as potentially significant contributors to the substantial variability in disease progression seen among HIV-infected people. Successful coping, however, is likely to reflect a close fit between external resources (such as informational, emotional, and social support) and internal resources, such a personality and motivational factors. The proposed research will focus on the role played by sociability, a fundamental component of personality, in the immunodeficiency disease process. The SIV-macaque model of HIV infection will be used, and two experiments are planned. In the first experiment, detailed behavioral and physiological data (including neuroendocrine, immunological, and virological) will be obtained from SIV-inoculated rhesus monkeys. The focus will be on individual differences in the activation of the two major stress-response systems: the sympathoadrenal medullary and hypothalamic-pituitary-adrenal, during social interaction, and the consequences of these differences for progression of SIV disease. In the second experiment, animals high and low in sociability will be studied in standardized situations designed to elucidate the psychological correlates of sociability. Inoculated and control animals will be exposed to stable and unstable social conditions, in order to determine how personality factors and a stressful social milieu might interact to affect psychobiological functioning and disease outcome. Particular interest will be focused in both studies on the role played by stress-induced reactivation of cytomegalovirus, considered a potentially important cofactor in immunodeficiency disease progression. This research aims to provide important new information on the relationships between personality, social stress, and their behavioral, neuroendocrine, virological, and immunological sequelae in the course of immunodeficiency diseases. Data from this research program are likely to focus attention on the importance of personality factors in infectious disease processes and in psychosocial treatments aimed at providing HIV-infected persons with palliative care.